Homebrew PCBs

> What IC is this?  Do you have a link for a data sheet?
>

<http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1666>

i found another solution.
I will hardwire the chip for one cell, and then use a voltage divider for
the cell number.
I could use a 1*12 pos. switch with a resistor chain, or i could use a  
10-turn
pot (helipot), which is what i will do because i have one already.

The result it not only a solved problem, but i can also use this voltage
for a treshold voltage for a discharge circuit, which i couldn't if i use
the chargers internal divider.

I thought about the homebrew switch, and even made a layout.
one could wire the switch as needed from only one component in the library.
The bad thing is it is relatively big (around 6cm diameter).

Assembly would be as follows:
take a M6 screw.
Make the "wiper" from a piece of pcb, solder on suitable spring contacts  
(like
the fingers from a GND shield spring - sheetmetal) in the right places.
drill a 6mm hole in the center and solder to the screw (all the way up  
against
the screwhead. Put a washer on the screw, then stick it through the PCB.
put another washer on this side, a nut. now take another strip of FR4,  
solder
a "ball" type item on the end, and affix it with another nut to the screw  
(which
also counters the first nut).

the PCB would have two concentric rings of contacts, which are connected by
your contact, and outside of them a ring of
holes which suit the "ball" as a snap-in mechanism. To set endstops you'd  
simply
put a M3 screw in the appropriate holes.
If you couldn't picture the instructions above note that the contact wiper
is on one side of the PCB, and the "snap in" mechanism slides on the other  
side.
this is required if you don't want your snap in to slide over connecting  
tracks.

Not too hard to manufacture, and i bet it would work, but as said i will  
probably
not need it for this project any more.

ST